Carburetor



u I I IIIIIIIII J72 yer ate?" June 3, 1930. w. A. EDWARDS CARBURETORFiled Feb. 12 1925 r the mixture forming device.

Patented June 3, 1930 WILLIAM A. nnwanns, or cnrcaeo, rumors GABBUBETORApplication filed February The purpose of this invention is to providean improved construction of a fuel mixture forming device for internalcombustion engines particularly adapted for installation in connectionwith the engine of an automotive vehicle. It consists in the elementsand features of construction shown and described as indicated in theclaims. 1

In the drawings 1 Figure 1 is a diagrammatic view showing in dotted linethe chassis and engine of an automotive vehicle and in full line in sideelevation, a structure embodying this invention installed on the chassisin the relation to the fuel supply tank, engine, and fuel mixtureconduit contemplated by the construction of said device.

Figure 2 is a section at the line 22 on- Figure 3.

Figure 3 is a section at the line 3-3 on Figure 2. v

Figure 4 is a sectional view. similar to Figure 2 showing a detailmodification of Figure 5 is an enlarged detail of a, portion of Figure4, being a section in the same plane as Figure 4.

Figure 6 is a section at the line 66 on Figure 5.

Figure 7 is a horizontal detail section at the line 7-7 on Figure 3.

Figure 8 is a detail of a portion of Figure 3 on a large scale.

In the structure shown in the drawings it will be understood thattheengine is indicated in dotted line at A, A being the intake manifold;that the fuel mixture conduit leading to the engine is indicated indotted line at B, (a heating jacket not concerned in this inventionbeing shown in dotted line at C). The main fuel supply tank is shown at10, mounted in the customary position at the rear of the chassis andconnected by a pipe, 11, with a level-governing chamber'or float bowl,12, wherein the governed level is indicated by dotted line, m. thelevel-governing float being shown at 13 controlling the inlet valve, 14,all according to familiar construction of carburetor float bowls and thelike. A horizontal portion of the fuel mixture conduit, B,

12, 1925. Serial No. 8,704.

is shown at 15, formed integrally with the 1 float bowl and extendingcross-wise of the vehicle in the installation as illustrated. In thishorizontal portion of the fuel mixture conduit in the form of theinvention shown in Figures 2 and 3 there are provided a plurality ofVenturi bushings or sleeves (two being shown, but any larger numberbeing within the scope of the invention) these venturis being desirablypositioned in fairly close succession in the fuel mixture pipe, andbeing,-preferably for the specific purpose for which they areprovided,in plurality, constricted to diflerent degrees, the leastconstricted being first in order from the levelgoverning chamber, andsubsequent venturis being successively more' and more constricted, thatis, having their diameters at the apex of the constriction successivelyless and less from the first in the path of movement of the fuel mixturethrough the conduit to the last in order. For receiving these Venturisleeves or bushings, and 21, the fuel mixture pipe section, 15, is boredand the Venturi sleeves are fitted to the bore not so as to requiredrive fit, but so that they can be readily positioned withoutsubstantial leakage around them in said section, 15, being secured inposition as hereinafter described. From the lower part of thelevelgoverning chamber or float bowl, 12, a fuel duct, 16, leads outthrough the stem, 17, which projects from the intersection of the stemand cross member of a T-shaped boss, 18, 19, at right angles to bothsaid-stem and cross member, said boss being formed integrally with thefloat bowl, and from the intersection of the members. 18 and 19, of theboss, a vertical branch, 18, extends for making junction with theintegral fuel mixture conduit member or section 15. To produce a duct,19", the horizontal element, 19, of the cross-shaped, boss is bored fromend to end, intersecting the bore which forms the duct, 10, in themember, 17, of the boss leading from the float bowl, that bore, 16,being made from the outer end of the radially protruding stem, 17 of theboss. the outer end being threaded and permanently closed by a plug, 23.The bore in the vertical branch, 18, of the boss is counterbored fromthe lower end as seen at 25, forming a counter-sunk shoulder, 25 andthis counterbore is further counterbored as seen at 26, and the finalportion of the original bore at its entrance into the cavity of the fuelconduit section 15 is threaded to receive a bushing, 27, said bushingbeing reduced in diameter and'threaded toward the end for engaging thethread of the original bore and forming a shoulder for seating at theshoulder, 25. This bushing is axially bored from end to end andcounterbored from its lower end to form a needle valve seat, 27 back ofthe discharge end of said bushing. The Venturi bushing or sleeve, 21,has a radial bore from one side opening at the constric-,

tion of the Venturi passage, this radial bore being positioned anddiametered for protrusion thereinto of the end of the bushing, 27, whichhas the thread stripped from it for a distance equal to the thickness ofthe Venturi sleeve wall at that point, the bore in the Venturi sleeveinto which the bushing protrudes being diametered for snug fit of thestripped end of the bushing, 27. The lower end of the vertical branch,18, of the boss below the horizontal elements 17 and 19 is threaded toreceive a bushing, 30, screwed thereinto and having a shoulder at 31 forstopping and seatingleak-tight on the lower end of the boss. Thisbushing is threaded for engagement of the threaded stem, 40, of a needlevalve, 41, which seats at the valve seat described in the upper end ofthe bushing, 27, and is provided at its lower end with a suitable head,42, for manual operation, a stuffing box. 43. being provided on thereduced lower end of the bushing, 30, to prevent any leakage through thethread of the valve stem. The horizontal boss member, 19, bored from endto end as stated is counterbored from the right hand end, referring toFigure 2, nearly to the other end, to form a valve seat at 19, andthreaded at the first mentioned end for engagement with the threadedo'rtion, 22*, of the stern of a valve, 22, a. stui ng box, 23, beingprovided at the first mentioned end, and apipe, 50. being connected by acompressible coupling, 51, at the other end heyohd the valve seat. Thepipe, 50, extends up across and past the section, 15, of the fuelmixture conduit integral with the float bowl,

between said float bowl and said integral con-- duit section, and iscoupled by compressible couplings, 55, with an elbow fitting, 56, whichis screwed into the upper side of the fuel conduit section, 15, saidelbow having a shoul= der, 57. for stopping it leak-tight against saidsection, 15,'and extending from saidshoulder with sufiicient length toenter a counter-sink at.20 around a port, 20", discharging in theVenturi throat at the apex-of the constriction thereof. It willbeunderstood that the elbow fitting thus serves as a key to position andsecure the venturi, 20, in placevin the fuel mixture conduit section,15, as the bushing, I

27, serves to position and secure the ventnri, 21. I

In Figures 4, 5 and 6 there is shown a modification consisting inemploying a single Venturi sleeve or bushing instead of a plurality ofsuch Venturi bushings shown in the preceding figures. In thismodification the single Venturi sleeve, 60, has a peripheral groove, 61,encompassing the sleeve at the point of greatest constriction, its widthextending longitudinally of the sleeve a short distance both ways fromthe transaxial plane of the apex of the constriction; and at one side anaperture is made leading radially into the cavity of the bushingsubstantially at the transaxial plane of the apex of the constrictionthrough which protrudes the reduced terminal nipple, 63, of a bushing,63, having an axial bore, 63, said bushing being inserted in the bore ofa hollow boss, 15", protruding downward from the boss forming thehorizontal section, 15, of the fuel mixture conduit. The bore forinserting the bushing, 63, in the boss, 15'. is closed at the lower endby a plug, 15, and this boss has a laterally protruding axiallyapertured boss, 15, for coupling thereto one end of a pipe, 65, theother end of which is similarly coupled to the end of the horizontalmember, 17 of a cross-formed boss corresponding to the boss, 17, 19, ofthe form shown in Figure 3, which horizontal member, 17 and the stem 19.of said boss are bored to provide a duet for conducting the fuel fromthe float bowl by way of the pipe, 65, for discharge through the nipple,63, of the bushing, 63. In this form the horizontal boss member, 17*, isbored and counterbored and provided with needle valve and stufiing boxidentical in form and construction with the corresponding feature shownand described in Figure 2. -It will be understood that in this form theconnection leading laterally from the stem, 19, of the cross-shaped bossof the form shown in Figure 3 by way of the pipe, 26, is omitted. Inthis modification the single Venturi bushing or sleeve, 60, has a secondaperture, 61*, for fuel discharge bored radially from the peripheralgroove, 61, into the cavity of the Venturi bushing, at a positiondiametrically opposite that at which the nipple, 63, discharges.

Upon considering the structure above described it may be understood thatthe liquid fuel will be drawn from the level-governing chamber or floatbowl and discharged into the fuelmixture' conduit by virtue of thecinityof the flow-accelerating restriction furnished by the Venturi sleeve orbushing.

It will be seen that a certain minimum velocity of air flow will beneces s ar to take a minimum quantity of .fuel. from t e lowestdischarge port,as 27 in the venturi, 21, of the forms shown in Figures 2and 3, or

turi, 60, of the forms's own in Figures 4,

5 and 6. It may now be understood that the purpose of the inventionlisto causev the engine when running idle with the throttle valve nearlyclosed and thereby drawing a minimum quantity of air at a minimumvelocity through the venturi or venturis, to take only the minimumquantity of," fuel necessary to develo under load the increased velocityof air through the fuel mixture conduit willfhOt} automatically increasethe amount of drawn through the-lower discharge, at the Venturiconstriction, but also will cause,

{5 only fue additional fuel dischargeyat the more elevated port'whetherin the'fisame venturi as so in the forms shownin Figures-4, 5' and 6,

or at a separate 'venturiflocatedfat,another point in thefuel'mixturej'conduiti Since the air velocity: through the venturi withany given engine speed,and' throttle opening will be greater as therestriction is greater,.that is, makin cross-section of the .air path atthe point '0 constriction less;-

there is an advantage in pluralizing the Venturi-sleeves or bushings, ascompared with 40 fuel dischargesres ectivelyat the up' er and lowersides thereo because with ap urality of venturis, the venturi which hasthe-fuel discharge into it at the higher point, as at the upper side,may also have itsflthroat opening greater, that is, less restricted, sothat at the point at which greater air velocity is necessary toproduce'liquid flow, higher speed of the engine andwider 0 ening of throttle,may be necessaryto p ace a given velocity of air flow. From thefor-egoing it will be understood that in any given construction ofventuri and position of the fuel discharge port therein, the ratio offuel first rises from a minimum, beginning when the air depression atthe point of fuel dis.- charge into-the venturi becomes suificient tolift the fuel to that point, u to the stage at which fuel isliftedsutficlently'to keep the fuel passagefull and the friction-10ffuel flow reaches a certain degree; and then, as

the engine speed increases and the increasmg air friction through theventuri causes retardment of the air flow, this retardment the nipple,63, of the forms shown in Fig-- the energy sufficientgo for operatin theengine at idling speed'with' g' out load, an upon opening the throttle:forjinereasing the engine speed and operatin it? v50w, at the venturihaving'the lower discharge,

and those which begin-to produce fuel dis;

using only a single Venturi sleeve vwith the flow to engine speed andresulting air flowgradually causes the ratio of fuel to the air todecline. From this it results thatwhen there is provided only one fueldischarge,

which is therefore in only one unchanging relation to one and the same-ven turi, the 1 maximum work per unit, of fuel consumedis obtained onlyat one stage of operating conditions in respect to engine speed andload,and at any lower or higher speed and load the amount ofwork derived froma unit of fuel is below the maximum. The construction described tends toobviate this defeet by the arrangements of the several fuel dischargesin relation to the venturi or'venturis into which they all respectivelydisso charge; so that decline of fuel supply'ratlo' to air supply at onedischarge overlafig. increase in such ratio at another fuel-disc a'rge,

vWhen employing this means for the purof engine speed and throttleopenin be tween those which produce fuel disc arge charge at the venturihaving the fuel dison charge at thev ,higher levelfmay be much widerthan 'ifthe two ,fuel discharges were into the same venturi," or in twoventuris hav;

ing the same constriction.-'=' The importance of the rovision shown forcausing increase of liquid fuel supplied at a certain stage in theincrease of engine speed and consequent increase of-air velocity,'notwithstanding the fact that the mere increase of air velocity tendsto cause increase of fuel 10o flow through the same discharge from thesame source, arises from the fact, ascertained by critical observatm'nof internal combustion engine operation, that with any given venturi .orother form of flow-accelerating restriction 5 I in thefuel' mixturecondult, the rate of increase of liquid fuel discharge, resultant fromincreased air velocity through. the venturi, diminishes from a certainpoint, that is,

' be the cause of this phenomenon, (sometimes attributed to skinfriction increasing faster than the air velocity increases), it is important to provide means for continuing the increase of fuel content in thefuel, mixture after the air velocity has passed the point at which itcauses an increase in the fuel supply .120

derived through a single duct ;v and the presv ent'invention providesmeans for accomplishing this purpose,

I claim pose indicaed it Wlll. be seen that the range 1. A fuel mixtureforming and feeding ap- 2 'paratus having in combination with a fuel 1mixture conduit, an initial air inlet, a governed level fuel chamber andfuel flow connections therefrom to said conduit, said con-' duitjhavingvarying cross sectional areas.

causing varying flow capacity at different portions of its lengthsubsequent to said initial air inlet and antecedent to any additionalair inlet, said conduit havin openings communicating with said fuel owconnections for fuel discharge in the conduit arranged successively atthe localities of said varying cross section and flow capacity, saidfuel openings being fixedly positioned at the respective cross sectionalareas, the discharge at any cross section of larger area being at higherlevel than the discharge at a cross section of lesser area, for causingthe decline of the ratio of fuel to air at one of said openings tooverlap in time of occurrence the riseof ratio at another of saidopenings.

2. A fuel mixture formlng and feeding apparatus having in combinationwith a fuel mixture conduit having an initial air inlet, a governedlevel fuel chamber and fuel flow connections therefrom to the fuelmixture conduit subsequent to said initial air inlet, said conduithaving a plurality of permanent constrictions, reducing it in crosssection in different degree for causing different acceleration of airflow at said constricted portions respectively, located in the conduitantecedent to any additional airinlet thereto, successively and in suchmanner that the entire air flow derived from the initial air inletpasses through all of said constricted portions in the order of theirsuccessive arrangement; said fuel flow connection having openings forfuel discharge in the conduit antecedent to any additional air inlet andinco-operative relation to said constrictions respectively, saidopenings being located relatively to the respective constrictionsdifferingly in respect to the areas of lowered pressure due to saidrespective constrictions, and difieringly in respect to the levels ofsaid openings relative to the governed level of the fuel chamber anopening at a constriction which reduces the cross section of the conduitin greater degree being at lower level, and an opening at a constrictionreducing the cross section of the conduit in lesser degree being athigher level.

3. A fuel mixture forming and feeding apparatus having in combinationwith a fuel mixture conduit having an initial air inlet, a governedlevel fuel chamber and fuel flow connections therefrom to the fuelmixture conduit subsequent to said initial air inlet, said conduithaving a plurality of permanent constrictions reducing it in crosssection for causing acceleration of air flow at said constrictedportions in the order of their successive arrangement, saidconstrictions differing in the degree to which they reduce the crosssection of the air path at the oints at which they are located, saidfuel ow connection having a plurality of openings for fuel discharge inthe conduitantecedent to any additional air inlet corresponding to theplurality of constrictions, and located in substantially the samerelations longitudinally of the conduit to theconstrictionsrespectively; whereby the amounts of fuel flow at thedifferent openings are functions of the degrees of ICStIlCtlOll at saidopenings respectively.

4. A fuel mixture forming and feeding apparatus having in combinationwith a fuel mixture conduit having an initial air inlet, a governedlevel fuel chamber and fuel flow connections therefrom to the fuelmixture conduit subsequent to said initial air inlet, said conduithaving a plurality of permanent constrictions reducing it in crosssection for causing acceleration of air flow at said constrictedportions, located in the conduit antecedent to any additional air inletthereto, successively and in such manner that the entire air flowderived from the initial air inlet passes through all of saidconstricted portions, in the order of their successive arrangement, saidconstrictions differing in the degree to which they reduce the crosssection of the air path at the points at which they are located, saidfuel flow connection having a plurality of openingssfor fuel dischargein the conduit antecedent to any additional air inlet corresponding tothe plurality of constrictions and Within the extent of saidconstrictions respectively, said fuel discharge openings being atdifferent levels with rela- %)ion to the governed level of the fuelcham- 5. A fuel mixture forming and feeding apparatus havin incombination with a fuel mixture conduit aving an initial air inlet, agoverned level fuel chamber and fuel flow connections therefrom to thefuel mixture conduit subsequent to said initial air inlet, said conduithaving a plurality of permanent constrictions reducing it in crosssection for causing acceleration of air fiow at said constrictedportions, located in the conduit antecedent to any additional air inletthereto, successively and in such manner that the entire air flowderived from the initial air inlet passes through all of saidconstricted portions in the order of their successive arrangement, saidconstrictions differing in the degree to which they reduce the crosssection of the air path at the points at which they are:

located, said fuel flow connection having a plurality of openings forfuel discharge in the'conduit antecedent to any additional air inletcorresponding in number to the pluralityof constrictions, and the fueldischarge openings being at different levels with relation to thegoverned level of the fuel chamber in the several constrictionsrespectively, the opening cooperating with the least constriction bemgat the highest level, and any opening co-operating witha greaterconstriction being at correspondingly lower level.

6. A fuel mixture forming and feeding apparatus having in combinationwith a fuel mixture conduit having an initial air inlet,

a governed level fuel chamber and fuel flowconnections therefrom to thefuel mixture conduit subsequent to said initial air inlet, J

said conduit having a plurality of permanent constrictions reducing itin cross section for causing acceleration of air flow at saidconstricted portions, located in the conduit antecedent to anyadditional air inlet thereto, successively and in such manner that theentire air flow derived from theinitial air inlet passes through all ofsaid constricted portions in the order of their successive arran ement,said constrictions differing in the egree to which they reduce the crosssection of the air path at the points at which they are located, saidfuel flow connection having a plurality of openings for fuel dischargein the conduit antecedent to an additional air inlet corresponding innum er to the plurality of constrictions, and the fuel dischargeopenings being at different levels with relation to the governed levelof the fuel chamber in the several constrictions respectively,

. the opening co-operating with the least constriction being at the hibest level, and any opening co-operating wit a greater constrictionbeing at correspondingly lower level, the fuel mixture conduit beingsubstantially horizontal at the location of the successive constrictionstherein, and the fuel discharge upper sides 0 said horizontal portion ofthe conduit whereby, regardless of the longitudinal separation of theconstrictions, the fuel discharge openings may be similarly relatedlongitudinally of the conduit to the respective constructions withoutdiffering in level more than the diameter of the conduit.

7. The construction defined in claim 6, the fuel mixture conduit havingthe horizontal portion comprising the successive constrictions, formedintegrally with the governed level fuel chamber, the fuel dischargesbeing by means of ducts formed in said integral structure leading fromthe fuel chamber for discharge respectively at the lower and upper sidesof the conduit proximate to the respective constrictions.

In testimony whereof, I have hereunto set my hand at Chicago, Illinois,this 6 day of February, 1924.

WILLIAM A. EDWARDS.

openin s bein res ectivel at the lower and g is P y

